Changes in the macromolecular structure of coals with pyrolysis temperature

Ndaji, Francis E.; Butterfield, I. M.; Thomas, K. Mark

doi:10.1016/s0016-2361(96)00175-5

Cited by 47 publications

(13 citation statements)

References 13 publications

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“…Abundant functional groups e.g. phenolic hydroxyl, ether, and alkyl side chains are substituted on the aromatic rings [30,31]. The formation of light gas species during coal pyrolysis is generally related to the decomposition of individual functional groups.…”

Section: Multi-component Analysis Of the Co Formation Mechanismsmentioning

confidence: 99%

Pyrolysis of superfine pulverized coal. Part 2. Mechanisms of carbon monoxide formation

Liu

Jiang

Shen

et al. 2014

Energy Conversion and Management

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Section: Multi-component Analysis Of the Co Formation Mechanismsmentioning

confidence: 99%

Pyrolysis of superfine pulverized coal. Part 2. Mechanisms of carbon monoxide formation

Liu

Jiang

Shen

et al. 2014

Energy Conversion and Management

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“…1995;Czapliński red. 1994;Ndaji et al 1997;Żyła red. 2000), and describing how different microlithotypes of coal behave as a result of injecting carbon dioxide into seams.…”

Section: Coal-bearing Series In the Upper-silesian Coal Basinmentioning

confidence: 99%

Zonation of deposits of hard coals of different porosity in the Upper Silesian Coal Basin

Bukowska

Sanetra

Wadas

2016

Gospodarka Surowcami Mineralnymi

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The article presents the results of tests of porosity of the Upper-Silesian Coal Basin (USCB) hard coals. The porosity was determined for various lithotypes of hard coal, collected in different areas of the Upper-Silesian Coal Basin. Samples of hard coal were collected in 60 seams of 16 coal mines, from the depth of approximately between 350 and 1200 m. There are also presented differences in values of open porosity of coal depending on the depth of occurrence, as well as chronostratigraphic and tectonic correlation of a seam. Uniaxial compression strength of the tested coals falls in the strength class from very low to very high (from 8.1 to 51.5 MPa), open porosity is 0.68–12.5% and total porosity is 3.29–17.45%. With an increase in depth, in general, open porosity of coals decreases. There is an apparent decrease in open porosity correlated with the age of hard coals. It was observed that the lower and upper limits of open porosity ranges of variability shift towards lower values the older the coals are, from the Łaziskie Beds to the Jaklowieckie Beds. The older the coals the greater the average drop in the share of open porosity in total porosity from 60% for the youngest coals to merely several per cent for the oldest ones. The highest values of total porosity (over 10%) were observed in the youngest coals (Cracow sandstone series and siltstone series). Older coals reached more diversified values of total porosity (3.29–17.45%). Based on the conducted tests, zones correlated with tectonics of the basin and with deposition of lithostratigraphic beds of specific age, where values of porosity of hard coals differ, were determined in the area of the USCB. However, in spite of their correlation to a structural unit, the coals demonstrated a decrease in open porosity with an increase in their geologic age. Thus, there is an apparent influence of the deposition depth of coal within a given structural unit on open porosity following the age of coal, i.e. correlation to an older and older chronostratigraphic unit. Porosity tests of hard coal are published in scientific journals yet, most often, there is no information on the type of porosity. Such detailed characteristics of open porosity for coal of the Upper Silesian Coal Basin, as in the article, have not been prepared yet, making our research novel. Such broad tests of porosity of hard coals, correlated with their strength and referring to the deposition depth of seams as well as a correlation to lithostratigraphic units within individual structural units in the USCB, had not been conducted yet. We believe it is a sufficient argument to start detailed research into the open porosity of hard coals. The results of the tests are important from both the research and practical points of view. Knowledge of coal porosity is indispensable in solving many engineering problems of geological engineering, mining geomechanics and mining e.g.: assessing behaviour of coal when it is mined and processed, assessing the possibility of capturing methane, which makes up over 90% of natural gas, from coal in the areas of methane-rich deposits; the possibility of storing various substances in abandoned hard coal mining areas (e.g. CO2 storage within the structure of coal), assessing risk of occurrence of certain natural hazards resulting from mining deposits (e.g. coal and rocks outburst hazard), as well as assessing the possibility of applying unconventional methods of mining hard coal deposits (e.g. underground coal gasification).

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“…A variety of substituents, such as hydroxyl, ether, ester, carboxyl, and alkyl groups are attached to the discrete/condensed aromatic rings in coal to form the main structure of coal macromolecules (Poutsma 1990;Ndaji et al 1997). Pyrolysis is a most generally used technology for downstream processing and clean utilizations of coal (Shabbar and Janajreh 2013).…”

Section: Introductionmentioning

confidence: 99%

Characteristics of gas evolution profiles during coal pyrolysis and its relation with the variation of functional groups

Zhang

Takeda

et al. 2017

Int J Coal Sci Technol

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Strict relation between the substituents or functional groups attached to the coal macromolecules and the generation of the volatile products, e.g., CH 4 , H 2 O, CO, CO 2 , etc., during the coal pyrolysis is an important but confusing subject. In this paper, quadrupole mass spectrometry, gas chromatography, and 13 C nuclear magnetic resonance are applied to real-time monitoring the formations of volatile products, off-line quantitative determination of the total products from the pyrolysis of a sub-bituminous coal (SC), and the changes of diverse substitents in the SC along with coke foamation, respectively. These measurements are also performed for the pyrolysis of a caking coal to contrast SC. The qualitative and quantitative data reveal that, during coal pyrolysis, the functional groups related with the formation of CO, i.e., ether, carbonyl, and anhydride, can directly generate CO via bond breaking, or take a detour of the formation of other intermediates via condensation and recombination firstly. Moreover, the formations of CO 2 and CH 4 are related to the direct removal of -COO-and -CH 3 , respectively.

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Changes in the macromolecular structure of coals with pyrolysis temperature

Cited by 47 publications

References 13 publications

Pyrolysis of superfine pulverized coal. Part 2. Mechanisms of carbon monoxide formation

Pyrolysis of superfine pulverized coal. Part 2. Mechanisms of carbon monoxide formation

Zonation of deposits of hard coals of different porosity in the Upper Silesian Coal Basin

Characteristics of gas evolution profiles during coal pyrolysis and its relation with the variation of functional groups

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